Art of making cast-in-place concrete piles and the like.



N. C. JOHNSON. AR'T 0F MAKING CASTINPLACE `CONCRETE PILES AND THE LIKE APPLICATION FILED IUNE 4. I9I5.

Patented Feb. '29, 1916.

www v10/aow e @Hom/wat NATHAN C. JOHNSON, OF ENGLEEVOD, NEW JERSEY.

ART MAKING CAST-N-PLACE CONCRETEEILES AND THE LIKE.

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Specification of Letters Patent.

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Application filed .Tune 4, 1915. Serial No. 32,175.

To all whom it may/concern:

Be it known that I, NATHAN C. JOHNSON, a citizen of the United States of America, and a resident of Englewood, county .oi Bergen, and State of New Jersey, have 1nvented a certain new and useful .Art of Making Cast-imPlace .Concrete Piles and the like, of which the following 1s a specification.

My invention relates to improvements 1n thf art of makingI cast-in-place concrete piles.

My invention is particularly yapplicable to that method of forming and placing concrete piles, wherein a suitable casing is driven into the ground, is then filled with plastic concrete and then the casing is withn drawn, perienced, in this method of pile driving, clue to the fact that the inward pressure, or back pressure, so called, of the surrounding earth, pinches off or squeezes aside the plastic concrete before it has had time' to harden, so that the continuity of the concrete pile or column is interrupted. .My invention omprises improvements in methods of castin and placing such piles, and particularly in the hardening of the concrete of such piles, and improvements in aplparatus for placing or forming such p1 es.

The object of my invention is to cause the concrete of such piles to set very rapidly and thereby to avoid pinching off or squeez,-

ing aside of the concrete, as hereinbefore referred to; and to do this in a simple manner and by simple means. l

will now proceed to describe my invenf tion withy reference to the accompanying drawings, in which various forms of apparatus adapted for carrying out the method portion of my invention and embodying the apparatus portion of my invention, are illustrated, and' will then point out the novel features in claims.

In said drawings: Figure l shows a top view of a pile-casing provided with heating means adapted for the carrying out of my invention, and Fig. 2 shows a central vertical section of the same, the casing being shown as provided with an alligator point, and being shown as-partly raised.

Fig. 3 shows a central vertical section of an Heretofore difliculty has been eX- Fig. 4 is a In the art of making eastin-place con crete piles of the type known as the sin1 plex pile, it is customary to drive into the ground a pipe or casing of appropriate diameter, furnished either with a solid point, or with a point known as an alligator point, at Lits lower end. After driving to a proper; refusal or penetration, the -pipe is filled with plastic concrete and gradually withdrawn from the ground by means of tackles. The plastic concrete then 4flows fromy the lower end of the pipe, the solid point, if used,`becoming detached from` the A pipe and being left permanently in the ground; whilecif the alligator .point has been used, the jaws open, leaving substantially a .free passage for the plastic cons cretegsuch concrete, in either` case, filling the space occupied Aby the vcasing previous to its withdrawal.. This type of pile is,

however, lopen to the very serious objection` thatthe yinward pressure, or back pressure,

so called, f the' surrounding earth, often pinches 0H; or squeezes aside, the plastic concrete, before it has had time to harden, so that the continuity of the concrete pile or column is interrupted.

lt is a property of Portland cement concrete that, while under ordinary conditions of temperature it becomes rigid at a period varying frorng one to three hours after its admixture with water, this' period will be very much shortened ify the temperature of the mass be raised well above ordinary atmospheric temperatures, the concrete set- Ating the more rapidly the higher the temperature is raised.

My invention comprises a method of and means for raising the temperature of the concrete approximately at the time of its .issuance from the lower end of the driven the concrete column as the driven casing is.

withdrawn.

For' applying heat to the concrete, I may inject steam ,into the concrete', through a suit?- able pipe,which initially is lowered to near the bottom lof the casing and then is withdrawn, either with the withdrawal of the casing or independently, thereby applying heat progressively, iirst to the concrete at the bottom of the hole and then upward. The steam, so ejected into the mass of liquid concrete, is condensed, so that not only the sensible heat of the steam, but also the latent heat of Athe steam is utilized, for heating the concrete; the water formed by thecondensation of the steam supplying. ing part the water required for setting of .the concrete. Or, steam, of the Water or other suitable heating fluid, may'be circulated throu h a pipe coil and 'then discharged outside o the hole; or, a suitable gas or liquid fuel burner may be operated within the concrete; or an electric heater maybe u sed as the heating means; in fact, any suitable means for applying heat may be employed. s

In the arrangement shown in Figs. 1 and 2, 1l designates a driven tube or casing, such as is commonly employed in forming and placing piles of the type described, 2-2 designates segments of a so-called alligator point, B designates a mass of concrete withinl the'hole and tube, 4 designates an annular perforated steam pipe, and 5 a pipe .for the supply of steam to such annular pipe 4. In Fig. 2 the tube 1 ,is shown 'as partly withdrawn, the alligator point having opened and allowed the concrete within the tube to fill the hole. The particular type of casing tube 1 there shown is provided near its bottom with a shoulder 6, and the annular steam pipe 4'is shown as located underneath such shoulder so that .it receives some .protection from the said shoulder. -It will be obvious that as the tube 1 and the steam pipes 4 5 are drawn up, steam will be supplied successively to all portions of the concrete; thereby greatly hastening the set ofthe concrete 'as already stated. But while, under the influence of heat applied as described, the concrete sets very rapidly, yet it does not set so rapidly as to prevent the withdrawal of the tube 1 with its point 2 and the steam pipes.

It is not necessary to 'suse a driven tube having an alligator point, or a driven tube having a shoulder forming a protection for the steam pipe 4. In the arrangement shown in Fi g.. 3, a plain point, 2a, for the tube l, is shown, this point remaining at the bottom of the hole when the tube 1a is removed; and this tube 1L is shown as a plain tube, the steam supply annulus 4EL being also shown as of considerably smaller diameter than the driven tube 1a. steam annulus might have any suitable diameter.` Under some conditions it may be advisable to have the steam discharged close tothe walls of the driven tube l, While under other conditionsgit may bev advantageou's to have the steam' discharged into the concrete more nearthe center ofthe mass of concrete, so that the steam is distributed more evenly through the concrete. It is not necessary to use a steam discharge annulus, as shown in Figs. 2 and 3, but the steam may be discharged from the open lower end ofthe straight pipe 5a,l asi indicated in Fig. 4. In fact, any Isuitable means may be used for distributing the steam, or no particular means whatever for distributing the steam may be employed, -and I do not limit myself vto the use of means for distributing the steam, or to any particular means for so distributing the steam.

It is obvious that this In the arrangement shown in Fig. 5, a

heatingcoil 4b is provided', having both a supply plpe 5 and a discharge pipe, 7 and `either steam, or hot water, or any other suitable heating fluid hay bel circulated v .through this coil 4" and,` thence outward.. The arrangement shown in F ig. 5 has the, advantage that the temperature of the heat fluid may be regulated very accurately and through a wide range, and thereby localized heating lto a temperature possibly higher vthan desirable, under some conditions, is avoided.

yand the air from the pipe 11', mixing Within the combustion chamber 13 and burning there, the products of combustion passing off through the discharge pipe 14.

In the arrangement shown in Fig. 8 an electric heater 15- is employed, the current being supplied to this heater through leads 16.

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In general, it maybe said that my invention is independent of any particular means for applying the heat.

It isnot necessary even to use a solid driven tube of the type shown. It is quite practicable to drive a collapsible mandrel, 5

thereby forming in the earth the hole for the pile, t'o pour the concrete through the mandrel into the hole, and then to withdraw the mandrel. In a companion application filed June 4, 1915, Serial No. 32,173., I have illustrated one suitable type of mandrel for this purpose. Heating means may be inserted into the hole formed by the use of that man- Afore set forth.

interim-Ey 0T exe'ioy, to the concrete hm heaingj mean drawn either w'fh ih@ mandrel, Gr befana c1' :4 withdrawn. Smizrly shown in the v panying dzrwfi Withd'avv'n bei@ layers wi i point nesess material, Eea stantia mamme means a hard o, the nierm the ur a..y ers Cen feng-n to sure of ik@ earth of? of the pile mf Surah a leaving me saa-e? a an agement Wod 

